Dim speed

Sub Wait(waitTime As Long)
    Start = Timer
    While Timer < Start + waitTime
        DoEvents
    Wend
End Sub

Sub HowFast()
    speed = InputBox("How fast do you read [fast, medium, slow]?")
        ActivePresentation.SlideShowWindow.View.Next
End Sub

Sub Pause()
    If speed = "fast" Then
        Wait (5)
    ElseIf speed = "medium" Then
        Wait (10)
    Else
        Wait (15)
    End If
End Sub

'Loop through the remaining slides at the designated speed
Sub AutoAdvance()
    For i = ActivePresentation.SlideShowWindow.View.Slide.SlideIndex _
        To ActivePresentation.Slides.Count - 1
        ActivePresentation.SlideShowWindow.View.Next
        Pause
    Next i
End Sub